A numerical study has been performed to study the fluid flow and convective heat transfer inside a rotating square isothermal channel with the channel cross-section having oblique angles to the rotational axis. The channel is subjected to a radial rotation. Computations are carried out for flows at Re = 500, 1000 and 2000 and range from the channel entrance to a flow distance of 300 and 600 times the hydraulic diameter, depending upon the Reynolds number. Results reveal the vortex flow structures, and consequently the heat transfer phenomena, are quite different from that of previous studies with zero oblique angle. The channel with 45 degree oblique angle yields the best overall heat transfer performance.